Method for making bomb heads or the like



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METHOD FOR MAKING BOMB HEADS OR' THE LIKE Filed Dec. 9, 1953 4 Sheets-Sheet 4 E 11 F JZ I 1 I 1 H I KP'I U I 0 I I 5 k l 51 ,7 i 15 19 J f 15 n A! George A/berz Lym METHOD FOR MAKING BOMB HEADS OR THE LIKE George Albert lLyon, 13881 W. Chicago Blvd., Detroit 28, Mich.

Filed Dec. 9, 1953, Ser. No. 397,248 9 Claims. (Cl. 29- -13) The present invention relates to the manufacture of the head shells of large size implements of destruction for ordnance use, such as lo'w'drag bombs.

Because of large size and thin 'wall requirements ordnanee bombs have customarily been made up, in the shell components thereof, from a plurality of components such as steel plate bent into shape and butt-welded into the shell shape. The heads of such bombs, and more particularly of the type of bomb referred to as low drag having a long tapered nose similar to a cannon shell have presented an especially 'difiicult problem from a manufacturing standpoint because of the requirement for quite thin main tubular body wall thickness while nevertheless requiring substantial mass of metal not only at'the 'base endportion but also at the tip end portion for attachment thereto of components that must necessarily 'be formed separately and assembled therewith.

An important object of the present invention is to provide an improved method and means for making large size shell heads adapted for use in ordnance aircraft rent bombs by drawingthe same from single disks or blanks of material such as steel slab.

Another object of the invention is to'provide an improved method for making bombheads or the like by drawing the'same to produce an efhcient distribution of material in the nose portion thereof.

A further object of the invention is to'provide'an improved method and means for nosing drawn'bomb heads.

Still another object of the invention is to provide a novel method and means for taper-nosing thin wall, thickened nose drawn head shells without collapsing of the thin walls during the nosing operation.

Other objects, features and advantages of'thepi'esent invention will be readily apparent'from the following detailed description of certain preferred embodiments thereof taken in conjunction with the accompanying drawings, in which:

Figure 1 is a transverse sectional view through a metal blank to be drawn into shell form;

Figure 2 is a transverse or vertical sectional view through the blank following a cupping operation;

Figure 3 is a similar sectional view showing the cupped blank following a drawing operation;

Figure 4 is a similar sectional view showing the drawn cup following a second drawing operation;

Figure 5 is a vertical sectional view'through the partially drawn shell following a third drawing operation;

Figure 6 is a sectional view showing the shell following a fourth drawing operation;

Figure 7 is a vertical sectional view through the shell following a fifth drawing operation;

Figure 8 is a vertical sectional View through the drawn shell and nosing apparatus, on a reduced scale;

Figure 9 is a vertical sectional view similar to Figure 8 showing the apparatus and shell at the completion of the nosing operation;

Figure 10 is a transverse sectional view taken substantially on the line XX of Figure 9;

Figure 11 is a vertical sectional view through the drawn shell associated with internal anti-collapsing means prior to nosing; and I Figure 12 is a vertical sectional view similar to Figure ice 2 11 showing the shell and the anti-collapsing means following nosing o'f the shell.

In the production of a bomb head according to the present invention, a sheet metal disk 15 (Fig. 1) comprising a circular slab of rolled steel of suitable grade is provided. For making a low drag bomb head for a bomb of say 1000 pounds, the disk blank 15 may be, for example, of approximately 40 inches in diameter and 1 /2 inches thick. By preference the edge of the blank 15 is slightly uniformly chamfered as at 17.

As the first step in shaping the blank 15, it is cupped as shown in dash outline in Figure 1 and in full outline in Fig. 2. The face of the blank from which the edge chamfer or taper 17 extends, that is the largest diameter face, is disposed to become the inside of the 'cup. At the conclusion of the cupping operation, the blank has a concave 'convex bottom wall 18 and a cylindrical side wall 19 of approximately the same thickness as the original blank.

Following the cupping operation, the cup 15 is subjected to a series of drawing operations during which the base wall 18 remains of substantially thesame thickness but'is progressively reduced in diameter as the'cylindrical wall 19 is progressively elongated and reduced not only in thickness but in diameter. Thus, in the first draw as depicted in dash outline in Fig. 2 and in full outline in Fig. 3, quite a reduction in diameter of the wall 19 is effected and substantial elongation to approximately twice the original cupped length of the side wall without much, if any, reduction in wall thickness, the material derived from reduction in diameter being primarily relied upon for the elongation. In the second draw the outside diameter of the side wall 19 is only relatively slightly reduced, on the order of approximately the first draw thickness of the side wall, whilethe thickness of the side wall is substantially reduced and the wall is elongated to approximately twice the'length to which it was drawn in the first draw. Thes'ize of a shell at theend of the second draw is shown in dash outline in Fig. 3 and in fulloutline in Fig. 4. Control of the length of the drawn shell may now'be eirected'by trimming off a predetermined marginal portion of the side wall 19 as along a line T indicatedin Fig. 3, with the trimmed length shown in Fig. 4.

In the third draw,the side wall 19 is further reduced in outside diameter and is elongated except for a portion of predetermined length at its upper marginal extremity which is left atthe same thickness and outside diameter as at the conclusion of the second draw. External surface juncture of'the thicker terminal marginal portion 20 with the remainder of the outside surface of the wall 19 is effected on a tapered juncture 21 (Fig. 5).

At the conclusion of the fourth and final diameter reducing and elongation draw of the side wall 19 (Fig. 6), the principal length of the side wall is drawn to the reduced diameter and thickness and is elongated, but a second portion 22 contiguous the thicker marginal portion 20 is left at the same thickness and external diameter as at the conclusion of the third draw. Juncture of the intermediate thickness portion 22 with the balance of the reduced diameter portion of the wall 19 is effected by a tapering external juncture 23. As a result, the major extent of the side wall 19 is now of the desired thin section and inside and outside diameter, while the nose end portion of the side wall is provided with the graduated extra thickness portions 20 and 22 on its outside diameter while the inside diameter of the wall 19 is uniformly cylindrical throughout to accommodate the drawing punch.

Following the final reduction draw of the side wall 19, the shell is subjected to a coin heading operation of the base 18 and a back tapering as at 24 of the side wall 19 (Fig. 7). Following this, the multi or stepped thickness nose portion of the side wall 19 is subjected to a final drawing operation wherein the marginal and intermediate thicker portions 20 and 22 are elongated and shaped to a uniform tapered nose thickness 25. After removal of the taper drawing punch, the nose taper thickened portion 25 is subjected to a contracting operation wherein the outside diameter is reduced to a preferably cylindrical continuity of the side wall 19, with the nose thickness at the inside of the shell as shown in dash outline in Fig. 7 and in full outline in Fig. 8.

As the final step in shaping the shell 15, it is nosetapered as shown in Fig. 9. This is effected in nosing apparatus depicted in Figs. 8 and 9 constructed and arranged to effect the nose tapering by uniform radially inward contraction of the thickened nose portion 25 of the shell.

The nosing apparatus comprises a die structure including means for supporting the base end portion of the shell 15 and comprising a base member 27 to which is attached a shell base supporting block 28 having therein a cavity 26 shaped complementary to the back tapered portion 24 of the shell wall 19. In the bottom portion of the cavity 26 is a stripper plunger 29 having attached to the lower end portion thereof an actuating rod 30 extending reciprocably through a bore 31 in the base member 27. Connection of the operating rod 30 to the stripper plunger 29 is effected through the medium of a reduced diameter head boss 32 on the rod extending into a complementary press-fit bore in the base of the plunger, with access to the tip of the head boss by a punch-out tool through an axial bore 33 opening through the top of the plunger 29 and normally closed by a screw plug 34. At its base end the plunger 29 normally rests solidly on the base member 27 so as solidly to support the headed base wall 18 of the shell to the external contour of which the tip or head end of the plunger 29 is complementary in shape. A predetermined range of stripping reciprocation of the plunger 29 is enabled between opposing axially directed limit shoulders 34 and 35 on respectively the plunger and the base block 28 within which the plunger is mounted.

Operatively cooperable in relatively reciprocable relation with the base block 28 is a nosing die block 37 supported by a head member 38 which may be operatively related to the ram of a press. Within the nosing block 38 is a nosing cavity 39 having the tapered shape to which it is desired finally to form the nose of the shell 15. Reciprocably mounted in normally retracted position at the tip or upper end of the cavity 39 is a stripper punch 40 having a stem 41 projecting upwardly reciprocably through the head member 38 and carrying an upper or head end collar or head block 42. A coiled compression spring 43 thrusting against the underside of the head 42 and at its opposite end within a recess 44 in the head member 38 about the stem 41 normally biases the plunger 40 into retracted position but is yieldable upon engagement of the head 42 with a stop (not shown) to enable projection of the stripping plunger 40 into the cavity 39 for ejecting the nosed shell therefrom.

In operation, the shell 15 is centered between the base block 28 and the nosing die 37 as seen in Fig. 8, and then the nosing die and base block are relatively reciprocably closed toward one another, as for example, by driving of the nosing die toward the base block to effect driving of the thickened nose portion 25 of the shell 15 into the nosing cavity 39 whereby the shell is taper nosed as shown in Fig. 9. By the contraction thus effected, the tapered nose portion of the shell is provided with substantially increased wall thickness attaining maximum thickness at the nose tip of the shell. This affords adequate material for subsequent internal machining and threading to receive a fuse tip or plug or armor piercing point on the head. At the conclusion of the nosing operation, the dies are separated, the stripper plunger 29 ejecting the shell from the base 28, and the stripper plunger 40 acting, after the shell has been carried by the nosing die 37 away from the base 28 to strip and eject the shell from the nosing die.

During the nosing operation, not only is radially inward compression and contraction of the nose portion 25 of the shell effected, but a considerable axial compression force is applied in driving the nose portion of the shell into the nosing cavity 39. Since the major extent of the wall 19 of the shell is comparatively quite thin, the axial compression force tends to cause buckling of the side wall. In the approximately first half of the nosing stroke of the nosing die assembly, while the nose portion 25 of the shell is moving into the larger gradually tapering portion of the nosing cavity 39, the axial compression force is reasonably moderate since resistance of the nose material of the shell to contraction is still moderate. However, maximum compression force is exerted in the last portion of the nosing stroke and it is at this time that the tendency toward buckling of the side wall 19 of the shell is greatest.

According to the present invention, the side wall 19 is supported against buckling during the greatest compression strain thereon during nosing. To this end, the base block 28 and the nosing die 37 are provided with complementary cooperatively related relatively axially movable alternating respective anti-buckling fingers 45 and 47 which become operative during the last portion of the nosing stroke of the die assembly and by their symmetrical radial external support of the side wall throughout the potential buckling zone as the nosing operation progresses to a conclusion prevent lateral or radial outward buckling of the shell. On inspection of Fig. 10 it will be observed that the anti-buckling fingers 45 and 47 have their major transverse extent radial relative to the shell so that they are strongly resistant to radial outward force exerted thereagainst by the shell wall 19. Additional reinforcement against radially outward displacement of the fingers 45 and 47 is afiorded by a reinforcing annulus collar 48 which may, for convenience, be mounted about the fingers 47 of the nosing die and secured to the nosing die as best seen in Figs. 8 and 9. Air pressure relief through the reinforcing ring 48 is afforded through one or more exhaust ports 49 therethrough preferably adjacent to the roots of the fingers 47.

In addition to external support against buckling of the side wall 19 of the shell during nosing, internal support against buckling may be provided as, for example, by filling the inner portion of the shell below the thickened nose portion 25 with lead 59 as seen in Figs. 11 and 12. In order to reduce the amount of lead required, a core member 51 of smaller diameter than the inside diameter of the shell is preferably mounted therein and the lead 50 is poured in molten condition into the uniform annular space between the core member 51 and the shell wall 19. The core member 51 thus serves as a lead minimizing element and also as a reinforcement against undesirable radially inward yielding of the lead fill.

In order to center the core member 51 within the shell, a reduced diameter base end boss or pin 52 is provided on the core member to fit in a suitable central bore 53 in the base wall 18 of the shell. Thereby the core member 51 is held against displacement as the molten lead is poured into the shell and the core member will, of course, be held quite firmly in place when the lead solidifies.

Following the nosing operation, the nose end of the shell is, of course, closed so that although the core member 51 was inserted into the shell through the nose end thereof before the nosing operation, it is now trapped within the shell. Accordingly, the base 18 of the shell is cored out or apertured along a circular line S to a slightly greater diameter than the core cylinder 51 and a central plug of material carrying the core member is removed to remove the core member following melting and removal of the lead 50 from the shell through the contracted nose opening of the shell.

It will be understood that modifications and variations may be effected without departing from the scope of the novel concepts of the present invention.

I claim as my invention:

1. In a method of making bomb head shells or the like, cupping a metallic disk, successively drawing the side wall of the cupped disk to elongate and reduce the diameter thereof, in successive drawing steps stopping the drawing of the nose end portion of the side wall short of the end thereof to provide a plurality of annular areas of graduated thickness, drawing said areas into tapered elongation terminating in greatest thickness at the edge of said wall, contracting the tapered portion thus formed to the inner side of the shell, and taper-nosing the nose end portion of the shell including said tapered portion.

2. In a method of making shell casings, cupping and partially drawing a metal blank into elongated cup shape with a generally cylindrical wall, progressively elongating and reducing the cylindrical wall and forming the margin thereof with an outwardly flaring thickness greater than the major extent of said wall, back-tapering the portion of the wall adjacent the base of the shell, contracting said thickened marginal portion to substantially cylindrical form concentric with the outer periphery of the shell wall throughout the major extent thereof, and taper-nosing said marginal portion of the shell.

3. In a method of drawing bomb head shells or the like wherein a metal blank of substantial size is cupped and progressively partially drawn to generally elongated cup shape with a substantially cylindrical wall, the improvement which comprises in successive draws forming the marginal portion of the wall with a plurality of graduated annular areas of greater thickness than the major portion of the wall, and drawing said graduated areas into a substantially continuous outwardly tapering progressively thickening area to the edge of said marginal portion of the wall.

4. In a method of drawing bomb head shells or the like wherein a metal blank of substantial size is cupped and progressively partially drawn to generally elongated cup shape with a substantially cylindrical wall, the improvement which comprises in successive draws forming the marginal portion of the wall with a plurality of graduated annular areas of greater thickness than the major portion of the wall, drawing said graduated areas into a substantially continuous outwardly tapering progressively thickening area to the edge of said marginal portion of the wall, and cylindrically contracting the marginal portion to conform the outer periphery thereof with the remaining major periphery of said wall.

5. In a method of drawing bomb head shells or the like wherein a metal blank of substantial size is cupped and progressively partially drawn to generally elongated cup shape with a substantially cylindrical wall, the improvement which comprises in successive draws forming the marginal portion of the wall with a plurality of graduated annular areas of greater thickness than the major portion of the wall, drawing said graduated areas into a substantially continuous outwardly tapering progressively thickening area to the edge of said marginal portion of the wall, cylindrically contracting the marginal portion to conform the outer periphery thereof with the remaining major periphery of said wall, and tapernosing said marginal portion while supporting the remainder of said wall against buckling.

6. In a method of drawing bomb head shells or the like wherein a metal blank of substantial size is cupped and progressively partially drawn to generally elongated cup shape with a substantially cylindrical wall, the improvement which comprises in successive draws forming the marginal portion of the wall with a plurality of graduated annular areas of greater thickness than the major portion of the wall, drawing said graduated areas into a substantially continuous outwardly tapering progressively thickening area to the edge of said marginal portion of the wall, cylindrically contracting the marginal portion to conform the outer periphery thereof with the remaining major periphery of said wall, and taper-nosing said marginal portion while supporting the remaining thinner portion of the wall both internally and externally against buckling.

7. In a method of nosing head shells, providing a generally cup-shaped shell, placing in the shell a core comprising a preformed core member and lead poured into the shell about said preformed core member into intimate contact uniformly with the internal surface of the shell wall, nosing the shell, and removing a portion of the bottom of the shell to eject the preformed core therefrom.

8. In a method of drawing bomb head shells or the like wherein a metal blank of substantial size is cupped and progressively partially drawn to generally elongated cup shape with a substantially cylindrical wall of substantial thickness, the improvement which comprises in successive draws elongating and reducing the thickness of the major extent of the wall but forming the margin portion of the wall with a plurality of graduated annular areas of greater thickness than the major portion of the wall while having substantially the same inside diameter inclusive of said major extent, and thereafter working said plurality of graduated annular areas of greater thickness into an ogive shell nose of a wall thickness that is pro gressively greater to the tip of the nose.

9. In a method of nosing shell casings having thin longitudinal walls and nose portions in which substantial mass of material must be contracted into the shell nose, placing within the shell casings a relatively high melting point core of smaller diameter than the inside diameter of the casings and shorter than the inside length of the casings and with the end of the core adjacent to the portion to be nosed extending substantially short of the tip of said portion to be nosed, filling in the space between the core and the inside wall of the casings with a low melting point metal in fluid state, solidifying the low melting point metal, nosing the casings, melting and removing the low melting point metal, and removing the high melting point material core.

References Cited in the file of this patent UNITED STATES PATENTS 19,918 Eaton Apr. 13, 1858 271,178 Wieser Jan. 23, 1883 887,950 Lindenborg May 19, 1908 977,639 Lachman Dec. 6, 1910 995,537 Cookingham June 20, 1911 1,059,212 Ross Apr. 15, 1913 1,617,491 Mallory Feb. 15, 1927 1,773,741 McNiff Aug. 26, 1930 1,891,304 Everett Dec. 20, 1932 2,023,727 Esser Dec. 10, 1935 2,067,568 Grunthal Jan. 12, 1937 2,202,042 Blount May 28, 1940 2,357,110 Heineman Aug. 29, 1944 2,371,716 Snell Mar. 20, 1945 2,377,097 Norris May 29, 1945 2,404,304 Layton July 16, 1946 2,446,672 Sirp Aug. 10, 1948 2,515,841 Stuart July 18, 1950 2,668,345 Eckstein Feb. 9, 1954 2,751,677 Mapes June 26, 1956 FOREIGN PATENTS 562,727 Great Britain July 13, 1944 OTHER REFERENCES Iron Age, Oct. 19, 1950, pp. 71 and 72. Machine Design, January 1946, p. 121. 

